# Explain preamps.

Discussion in 'Pickups & Electronics [BG]' started by Crazyman582, Feb 23, 2016.

1. ### Crazyman582

Dec 8, 2015
I understand what preamps do, just not how they do it.Could anyone explain this in electrical terms?

2. ### MonetBass♪ Just listen ♫Supporting Member

Sep 15, 2006
Tulsa, OK
5fingerfrenzy likes this.
3. ### Crazyman582

Dec 8, 2015
Looks good, thanks

4. ### line6man

You need to be specific. Preamps do a lot of things. What aspect of their function needs explanation?

5. ### Crazyman582

Dec 8, 2015
How they edit the signal to add eq

6. ### Rob22315

Oct 23, 2010
Alexandria Virginia
Preamp do four basic jobs. They buffer the signal from the pickup, they buffer the signal coming out, they provide gain control, and they shape the frequencies of the signal. A detailed understanding of these would get you a long way towards a degree in electrical engineering.

We can try to provide you with some simplified explanation of how these things are achieved. Which interests you?

7. ### ddnidd1Supporting Member

In order for anyone to answer your question in any meaningful way, they would need to know the depth of your knowledge and understanding of electronic theory.

8. ### Crazyman582

Dec 8, 2015
I have done some tinkering with soldering and I know my way around a breadboard and arduino. I understand the preamp changes the current, which is turned into sound by the amp. (I think). So assuming the above is true, how does it add/remove certain frequencys?

9. ### khutchPraise Harp

Aug 20, 2011
suburban Chicago
It is a fairly complex subject that is best explained with a lot of math that of necessity involves complex numbers so that both magnitude and phase of the voltages and currents can be properly accounted for. You can buy books on active RC filters and a web search on that subject should also turn up a lot of information. However from what you have said so far it is not clear that you have the electronic circuit theory background required to understand them. But web resources are free for the most part so have at it! In general terms resistor and capacitor networks are used to couple the outputs of the active amplifying stages back to their inputs and the frequency selective properties of the capacitors allows you to build circuits that will amplify or suppress the desired frequencies in a controlled fashion. Variable resistors (aka pots) can be used to allow the user to modify pretty much any characteristic of the resulting circuit. That is an exceedingly high level view but things get very complex very quickly as you try to go deeper into the theory. You will have to leave the typical TB simplified explanations far behind to understand what is really going on. I am not trying to discourage you but you may be best served by seeing if there are any electronics theory classes that you can take at local community colleges where you would get a lot more knowledge a lot more easily than we or a book or web page could give you. Now I assume that you are not a university student when I say this. If you are and you are really interested in this sort of thing then perhaps you should consider changing your major to electrical engineering!

10. ### lz4005

Oct 22, 2013
Nope. Sound is moving air. Speakers do that.

Dec 8, 2015